1. Technical Field
This invention relates to a row crop planter and, more particularly, to a planter unit having means for forming a seed trench, closing the seed trench and gauging planting depth.
2. Prior Art
Heretofore, others have provided disc openers for forming a seed trench. U.S. Pat. No. 564,604, for instance, discloses a pair of staggered discs for opening a seed trench. In U.S. Pat. No. 2,924,189, a pair of rearwardly converging vertical discs are employed to simultaneously mulch the marginal portions of the furrow and close the furrow or seed trench. The beforementioned discs may also be used to create mulch for small seeds deposited on top of the soil. In U.S. Pat. No. 2,691,353, a pair of discs are used to create a seed trench followed by a pair of discs employed to close the seed trench over deposited seed. In U.S. Pat. No. 3,450,074, a combined disc opener and gauge wheel is utilized for planting. In U.S. Pat. No. 2,685,243, a pair of planter gauge wheels are disposed at the laterally outer sides of a pair of disc openers with the gauge wheels individually vertically adjustable relative to the disc openers. In U.S. Pat. No. 4,009,668, a pair of gauge wheels are disposed at laterally opposite sides of a pair of disc openers and in rearwardly offset relation thereto so each gauge wheel engages the ground at about the point the associated disc opener leaves the ground.